Carbon monoxide poisoning in cars rare but deadly, experts say

The deaths of five young people in Alberta in less than a month are being linked to carbon monoxide poisoning in cars, prompting experts to warn drivers not to idle for too long and to ensure vehicles are properly maintained.

Three people in their 20s were found dead in a vehicle near Conklin, Alta. on Tuesday. Their families say they were told by the medical examiner that carbon monoxide poisoning was the cause.

Last month, teenagers Gage Bogart, 17, and his girlfriend Shaina Ridenour, 16, died after being found in an idling car in Drayton Valley.

Crystal Lavallee-Shirt is the sister of Cade Lavallee, one of the three people who died near Conklin. She described him as a great uncle and father. He had three children.

"I spoke with the medical examiner, they did confirm it was carbon monoxide poisoning," she said. "You think your vehicles are safe and you don't know."

The family of a young woman who was also found in the car says they want to warn other of potential dangers.

"In this cold weather, we want everyone to inform their loved ones not to leave their cars running," Emily Lawrence said. Her cousin, Tristan Dave-Lawrence, also died.

Exhaust problems cause concern

Experts say carbon monoxide poisoning is more typically associated with faulty furnace systems or other home appliances.

"Carbon monoxide poisoning from cars has become extremely rare in modern cars," said Raynald Marchand, general manager at the Canada Safety Council.

"That is in part [because of] the catalytic converter. The gas is heated to such a high temperature in the converter that it pretty much eliminates all of the bad stuff. So modern cars pollute way less and the carbon monoxide left over would typically give someone a headache but would not normally be sufficient to kill somebody."

Marchand said modern cars would include those that are approximately 11 years old or less.

Marchand said ìf a leak occurs "ahead" of the catalytic converter, it couldn't do its job properly and more carbon monoxide would be produced.

Randy Loyk, manager of technical services at the Alberta Motor Association, said many factors could affect a car's carbon monoxide emissions.

"Has your vehicle been properly maintained? Is the exhaust system good on your vehicle? If you do have a leak on your exhaust system, the potential is there for you to get carbon monoxide into the vehicle, especially if you're sitting there, in cold temperatures when no wind is blowing," he told CBC's Radio Active on Thursday.

"That carbon monoxide tends to hang around the vehicle. And if you're sitting there, running it, the heater system can pull it into the vehicle. It's not a good idea."

If a car gets stuck in a ditch or deep snow, clear the tail pipe of snow and ensure the path is clear for up to a metre behind the vehicle, Loyk suggested.

"Carbon monoxide can be pushed back underneath the vehicle and the [heating and ventilation] system can pull those fumes into your vehicle," he said.

"Make sure you clear your tail pipe, roll down your windows, try not to keep it running for too long."

Don't idle for long

Russell Croome, deputy chief of public safety for Edmonton Fire Rescue Services, said attached garages can pose problems if cars are started inside.

"If the wind is blowing into the garage then you're filling your garage with carbon monoxide, which may penetrate your door if you don't have a good seal going into the house," Croome said.

He said people should back their vehicles out of their garages if they want to warm them up before driving.